1. Field of the Invention
The present invention is directed to a water conserving device for use in toilets and, more particularly, to a flush valve which, through operation of a single flush handle, can be prematurely closed after the initiation of a flush.
2. Description of the Prior Art
Water, while plentiful in many areas of the world, is becoming increasingly limited or even scarce in many other areas. Unfortunately, water is often wasted--even where it is available in limited quantities.
One particular area which traditionally consumes more water than necessary and is thus responsible for wasting a significant amount of water is the toilet tank. Commonly used toilet tanks generally hold between three and four gallons of water and consume substantially all this water for each flush. Since the volume of water actually needed for flushing varies with the type and volume of waste, this use of a large, fixed volume for each flush is, over time, extremely wasteful. If, for example, in any community, one to two gallons would be saved per flush per toilet, this in turn would produce significant water savings in a very short period of time.
A variety of different types of water-conserving devices for use in toilets are known. For example, one type comprises one or more flexible wall surfaces or dams (sometimes referred to as "dikes") which are inserted into the toilet tank. These flexible walls are used to isolate a pre-determined quantity of water existing in the tank from the flush valve situated at the outlet of the tank. In effect, these devices form a water column, around the flush valve, which contains significantly less water than the total amount held by the tank. Since only the water existing in the water column is available for flushing, these dams do indeed conserve water. Illustrative examples of such structures are described in U.S. Pat. Nos. 4,250,579 (issued to J. R. Moon on Feb. 17, 1981); 4,080,667 (issued to R. M. Walsh et al on Mar. 28, 1978); 4,009,497 (also issued to J. R. Moon on Mar. 1, 1977); and 3,811,134 (issued to T. M. Throckmorton et al on May 21, 1974). Even though these dam type structures do save water, they can not release the full amount of water stored in the tank when required by the type and volume of waste to be flushed. Thus, these devices often produce incomplete flushes which subsequently require a second or even a third flush to completely expel the waste. Any water saving generated by the first flush is either balanced or out-weighed by the water required by the subsequent flushes.
Another type of water-conserving device involves those which permit both full and partial ("dual-mode") flushing, i.e. permit the release of all or a pre-selected fixed portion of the total water stored in the toilet tank. An illustrative device of this type is disclosed in U.S. Pat. No. 3,795,016 (issued to E. A. Eastman on Mar. 5, 1974). Here, two independent control valves are disposed at different water levels within the tank, and one or both of these valves are opened by downward rotation of a flush handle through a relatively small or an increased arc, respectively. While this device does permit either a full or partial flush, this device possesses various drawbacks. First, installation of this device is relatively complex. Second, and more important, users may often depress the flush handle with enough force to inadvertently initiate a full flush when only a partial flush is necessary--thereby wasting water. Third, by virtue of the relatively large fixed quantity of water consumed during a partial flush, water may still be wasted during such a flush if only liquid wastes need to be removed. Other dual-mode devices which suffer from one or more of these drawbacks are disclosed in U.S. Pat. Nos. 3,908,203 (issued to M. J. Jackson on Sept. 30, 1975); and 4,175,295 (issued to R.L. Cameron on Nov. 27, 1979).
Applicant, in his co-pending U.S. patent application Ser. No. 560,934 filed Dec. 13, 1983, discloses an effective dual-mode flush valve which eliminates many of the problems inherent in prior art dual-mode devices. However, applicant has recently discovered that, as a result of the size of his dual-mode device, this device may, when installed in certain rotational positions in the tank, partially prevent the arm running between the fill valve and its associated float from freely moving throughout its entire vertical range.
A third type of water conserving device involves those which pre-maturely close the flush valve. While this third type holds the most promise for achieving effective water conservation while avoiding the drawbacks inherent in the other types, prior art devices of this type also possess significant drawbacks which limit their widespread acceptance. For example, U.S. Pat. No. 4,038,708 (issued to P. M. Perrine et al on Aug. 2, 1977) discloses a device which is actuated by every flush. Since this device operates even when a full flush is required, ineffective flushing, requiring subsequent flushing and increased water consumption over that required for a single full flush, often results. Thus, this device suffers the same drawbacks as the dam type structures described above. This particular drawback is overcome in the structure disclosed in U.S. Pat. No. 4,135,262 (issued to C. A. Overbey on Jan. 23, 1979) in which a full flush can be obtained by inhibiting the flush valve from closing pre-maturely. Unfortunately, this structure requires the installation of another control, in addition to the flush handle, onto the exterior of the toilet tank. This second control, when depressed, allows the flush valve to close pre-maturely thereby producing a partial flush. Unfortunately, users, generally not accustomed to seeing two flush controls on a toilet tank, would well find use of a second control to be cumbersome and as a result might simply ignore its existence and thus forego conserving water. Moreover, many homeowners might regard the existence of a second control on the exterior of the tank as unaesthetic and/or installation of this structure as being too complex.
Other structures which rely on pre-maturely closing a flush valve are disclosed in U.S. Pat. Nos. 4,364,129 (issued to J. S. Schonger on Dec. 21, 1982); and 4,183,107 (issued to N. S. Hare et al on Jan. 15, 1980). While both these structures conserve water, are simple to install, and operate through the existant single flush handle found on a toilet, these structures do not close the flush valve sufficiently fast after the user releases the handle to terminate the flush. Thus, these structures disadvantageously waste some water although not nearly as much as other prior art devices.